Teac Tripath - thoughts to date

toobwacky · « **Reply #60 on:** 14 Nov 2004, 06:21 pm »

Regarding the power rating versus the power consumption, I suspect that what is happening is that any one of the 3 channels can produce its 30 watt rating, but the power supply isn't beefy enough for all 3 channels to deliver 30 watts simultaneously. This is a very common occurrence with multi-channel amps these days. Still, this is a great sounding amp.

My system is a Sony ES digital front driving the Teac amp directly from its headphone output. The Teac is driving a pair of Magnepan MMGWs, which are augmented on the low end with an active woofer. The MMGW's 5 ohm load is not the best electrical match for the Teac, but man, this combo makes music. To wring the last ounce of performance out of the Teac, I plan on replacing the input coupling caps with super high quality .025uf caps. If my math is correct, this should create a 6db/oct high-pass filter around 150hz that would be perfect for the Magneplanars.

mcgsxr · « **Reply #61 on:** 15 Nov 2004, 02:10 pm »

Interesting about replacing the coupling caps to roll off the sound. You are aware that there are two sets of coupling caps in the stock unit right? I believe GBB raised that point in another thread, but there are several people around here that could point it out to you - not unfortunately...

Those Maggies look interesting, are those the ones that can be wall mounted? That could certainly come in handy down the road...

lcrim · « **Reply #62 on:** 15 Nov 2004, 05:22 pm »

I heard some of what Geoff described earlier in the thread, the digital hardness and ringing on my livingroom system. I had the Teac right next to the preamp and apparently the emi was heard through the preamp on the playback of a vinyl repressing I received as a gift over the weekend.
I moved the Teac about 18" away from the pre and soldered in a Volex power chord (three wire, 14 guage, foil shield, grounded to chassis internally) upstream of the round thingy and these measures helped a lot but the damn record still sounded ringy. I have the same musical piece on SACD as well and that version was warmer and less digital sounding (Brubeck -Take Five) so I took the record to the bedroom system which is entirely tubed albeit not warm and romantic sounding (Decware Select.) It still had a hard edge and lots of groove noise. Verdict: Probably a lousy pressing.
Anyway, I started thinking about how to further improve the Teac and like someone earlier suggested, the switching power supply is the root of lots of the issues. You can clean up the signal path, yes, of course. But the switching power supply is most likely the cause of the emi and its only advantage is that its light. If you are shipping pallets of these things, then the costs are much less with the much lighter switching power supply.
Maybe someone with EE level knowledge could take a look at this and come up with a set of mods, much like VinnieR and John Swenson did with the Toshiba 3950. The potential upside would be huge for budget minded audiophools. (Note: I realize that Wayne @ Bolder Cable is working on this for Mark and no dis intended.)
The damn thing sounds so good already and is so cheap that I hate to give up on it because it lacks that last bit of refinement.

maxwalrath · « **Reply #63 on:** 15 Nov 2004, 05:50 pm »

There might be threads on this somewhere else in the lab, but would it be possible to change the power section of the amp around so it runs off of battery power?

ludavico · « **Reply #64 on:** 15 Nov 2004, 06:08 pm »

I decided to give "mono block" operation a try with the TEAC A-L700P using the center channel connections. I turned the pots on the L and R channels to minimum and cranked the pot for the center channel to maximum.

Shazaam.

I heard the difference right away. Could unloading the onboard power supply make this much difference?

I just ordered TEAC #2 from J&R...

Blissfully ignorant,
John

PS - Is it worthwhile (and easy) to pull out the unnecessay boards in the A-L700P for mono block operation (using the center channel only)?

mcgsxr · « **Reply #65 on:** 15 Nov 2004, 06:12 pm »

I cannot answer the useful part about pulling out the amp board, but it sure is simple - it just "plugs" into 3 "receivers" on the main board of the amp (bottom). Dead easy - pull out, slot in - similar to memory in a computer for example.

I think that I remember that some of the people who mod these amps pull the C board, and mod the L&R board. In my amp, being modded by Bolder, Wayne (at my request) converted the L&R board to just a single channel, and so I have two mono amps in one chassis, along with the rest of the upgrades.

ludavico · « **Reply #66 on:** 15 Nov 2004, 07:03 pm »

Thanks Mark.

When TEAC #2 arrives, I will yank the L&R amp boards.

Can't wait for the verdict on your mods....

I wrote to Wayne, and he said the full Monty for a A-L700P will probably be pretty reasonably priced.

Until then I am thinking about AC conditioning. But what is good, and cheap?

On the list so far: DIYCable JR filter, Transcendent BPS.

John

mcgsxr · « **Reply #67 on:** 15 Nov 2004, 07:06 pm »

Yeah, Wayne is very accomodating both in terms of pricing, and in terms of getting you closer to what you want to have.

I use a really cheap ($30 or so delivered...) OneAC unit off eBay - simple, 2 amp version, and it works for me, for both Teacs at the same time, when running HT. Might work for you.

Now, I am sure that there are better units, but I don't have the $$ to experiment and find it - perhaps you will!

Keep us up with how that works out for you, I know that there are others around eyeing up monoblocks for $199...

tianguis · « **Reply #68 on:** 16 Nov 2004, 12:01 am »

ludavico:
Although I don't have a TEAC, I have a modded Panny XR50, done along the lines of Wayne's mods. Balanced power reaps mucho benefits. I use a Transcendent BPS with large Bybees on both output legs. I've done critical listening to the Panny with and without the BPS. No contest. The BPS has enough capacity (and then some) to power all my equipment.

Regards,
Larry Welsh

AphileEarlyAdopter · « **Reply #69 on:** 16 Nov 2004, 12:59 am »

Larry,
How would you compare your TEAC with the Panny XR50 ?
Last week, I had an opportunity to listen to a TEAC with a Dared Tube Preamp. It was very good, but I could not tell much, because the whole system and room were totally different.
But one thing remained in my mind, my XR50 with balanced power conditioner sounds really, really 'quiet'. The TEAC with the tube preamp sounded very lush. Was very good with some Piano music (RCA Living Stereo CD/SACD) , even though all kinds of music had the same 'tinge'.

tianguis · « **Reply #70 on:** 16 Nov 2004, 01:53 am »

Aphile:
I don't have a TEAC (maybe, yet!). However, I've driven the Panny with a Transcendent Grounded Grid. Directt doesn't reduce anything, as far as I can tell.

Regards,
Larry Welsh

lcrim · « **Reply #71 on:** 16 Nov 2004, 03:40 am »

I'm now running a pair of Teacs with the L,R Tripath board removed and decent shielded power cables soldered in place. I had ordered a second unit from J&R last week and it arrived, so I spent some time with a screw driver and soldering iron and have been listening for a few hours only. Almost no burn-in on the new unit so it should improve but so far I think together they are an improvement over the single. Lots of finesse. Someone earlier in this thread referred to this as the "monoblock" setup. Whatever digital nastiness I complained of in a previous post has disappeared. The inner detail and air around instruments and voices has increased. Bass feels better damped. Lyrics have become more intelligible.
I have a bone stock XR50 as well, it is much more powerful for sure. The two Teacs are richer sounding though, thats a very appropriate comparison. I expect that there are speaker loads that will need the extra drive of the Panny.
Sounded best on SACD and directv music channels (amazingly good on these.) A little disappointed w/ vinyl playback but may be transparently showing the quality of the upstream components. The units also run cooler, heat near the power supply is much lower.

ludavico · « **Reply #72 on:** 16 Nov 2004, 03:15 pm »

Hi Larry,

You have already done the jump to "monoblocks", then. Excellent post.

When I hooked up my single TEAC A-L700P through the center channel connections to one of my speakers, I heard exactly what you described.

I ordered a second TEAC yesterday.

Do you think the benefits of power cord replacement are big? I ask because my first TEAC running in stereo reached the 150 hour mark sounding pretty bloody amazing. The glare and grit in the HF had dropped off a lot.

Are there any tricks to pulling the L&R amp board out?

Cheers,
John

PS - I am running into B&W 601 S2 standmounted monitors with ~89 dB sensitivity. I hear bad nastiness when I go to headbanger volume levels, but otherwise it is sweetness and light. My preamp is a Muse Model 3 which seems to bed well with the TEACs.

mcgsxr · « **Reply #73 on:** 16 Nov 2004, 03:22 pm »

Quote from: mcgsxr

I cannot answer the useful part about pulling out the amp board, but it sure is simple - it just "plugs" into 3 "receivers" on the main board of the amp (bottom). Dead easy - pull out, slot in - similar to memory in a computer for example.

I think that I remember that some of the people who mod these amps pull the C board, and mod the L&R board. In my amp, being modded by Bolder, Wayne (at my request) converted the L&R board to just a single channel, and so I have two mono amps in one chassis, along with the rest of the upgrades.

Pretty simple to remove the board - remove 1 screw from the rear of the unit - it holds the board upright. Then pull up on the board - it comes out like computer memory.

ludavico · « **Reply #74 on:** 16 Nov 2004, 03:24 pm »

To NYC Larry W.: I am the one who emailed you recently about the Transcendent BPS. You convinced me to buy one! Still pondering the GG, though.

Thanks again for the info.

John

lcrim · « **Reply #75 on:** 16 Nov 2004, 04:33 pm »

John wrote:Do you think the benefits of power cord replacement are big? I ask because my first TEAC running in stereo reached the 150 hour mark sounding pretty bloody amazing. The glare and grit in the HF had dropped off a lot.

(sorry, I can't figure out how to use this arcane billboard program)

Dmason made the (strong) suggestion that because the power supply is a source of emi that a decent shielded power chord was a wise addition. There is a round thingy, which I thought was a magnet but was informed that it is a toroid, which is attached to the stock chord, just before the connection to the power supply board. This is apparently intended to negate the emi. I soldered in a shielded chord and attached the shield to the chassis. Kept the toroid in the line. I didn't buy the $4 a foot 12AWG stuff but found a part at mouser.com which was ~$10 already made up w/ plug all from Volex. No $20 Marinco male plug.
I have heard power cables improve the sound of a component. I feel that replacing the power chord on these units with a reasonably priced improvement makes sense. Any audible improvement? Well , after removing the other chip (really simple BTW-Mark described this above) it is impossible to say what accomplished what. I was in there so I wanted to do all the stuff I was aware of in one shot then close it up and get on with listening.
Further listening last night confirmed my initial impressions. I was up late listening to lyrics I have never understood before, hearing the individual voices in a backup chorus, cymbals that are made of brass hit with a wooden stick, well you get the idea. I am really amazed at the quality of sound these buggers put out.

albee · « **Reply #76 on:** 16 Nov 2004, 04:59 pm »

Pardon my intrusion but learn me something . . .

Is the center channel of the Teac running mono? I noticed on mine that it was louder and needed to be set at lower gain. Because of the binding posts, I started using the right/center for stereo for quite a while. I just re-connected to the left/right channel just the other day. No apparent damage to the L/R board.

mcgsxr · « **Reply #77 on:** 16 Nov 2004, 05:30 pm »

Not sure if your question is - is the center board just running one channel"
OR is the center board bridged into mono?

I believe the answer is that it is just configured to run one channel, not bridging the two channels to produce one.

In any case, I had Wayne mod mine to have each board run one channel.

ludavico · « **Reply #78 on:** 16 Nov 2004, 06:37 pm »

Larry, thanks for the info. I think I am going to just pull the L,R amp boards when TEAC #2 arrives, and let things settle out before I try anything else. BTW, I just read that it takes 3 months for the Tripath boards to run-in!!??

So far, my findings agree completely with Mark's...something really significant happens at ~ 130-150 hours.

The dang thing is wildly above my expectations at this point.

Albee: sorry, I have no idea what differences a signal sees going through the L or R channel versus the C channel. My quick and dirty experiment was to disconnect the L and R channels, then hook up one of my speakers to the C channel. The difference was audible, and consistent with Larry's experience. Could it be just a matter of unloading the power supply?

Dunno...

John

MattS · « **Reply #79 on:** 17 Nov 2004, 05:23 pm »

I bought a Teac after reading all the good reviews here. I've had the Teac a week (50 hours on teac) and I am very pleased. I've paired the Teac with 4 ohm Magnepan Mg12s. The Teac drives the Magnepans very nicely and with surprising bass for 30 watt amp with more than enough volume. I will be trying the Teac with a pair of Klipsch Forte IIs which should be an even better match. With all the talk of running them as monoblocks, I couldn't stop myself from ordering another Teac.

Thanks all for sharing info about this nice inexpensive amp.